Synthesis and antimicrobial activity of pyrimidinophanes containing a uracil moiety and a bridging sulfur atom

Pyrimidinophanes containing one 5(6)-alkylsubstituted uracil moiety and a 10-or 12-methylene bridge including a sulfur atom were synthesized. The bridging S atoms of the macrocycles were converted to sulfonium groups by interaction with para-toluenesulfonate methyl or nonyl esters. The resulting amphiphilic pyrimidinophanes were tested for bacteriostatic and fungistatic activity against Gram-positive and Gram-negative bacteria and fungi. Amphiphilic pyrimidinophanes with 5-decyl-6-methyluracil moieties had high levels of bacteriostatic activity against Gram-positive bacteria. The minimum inhibitory concentration of the macrocycle containing a methyl group in the sulfonium grouping against Staphylococcus aureus was 0.75 !g/ml. These data are of value in seeking new highly effective antimicrobial agents.